The invention relates to card cages for housing of electronic circuit boards.
With the advent of the circuit board, now ubiquitous in all forms of electronic equipment, chassis and cabinetry for electronic circuitry changed markedly. In the architecture of circuit board housing, several competing functional interests must be resolved in order for form to truly follow function. Geometrical or space constraints, electrical requirements and so called human factors do not always mesh. The assembly of iterative circuitry represents one of the harder schemes to design well, i.e., creatively with enhanced functionality. The goal of housing numerous similar or identical circuit boards can give rise merely to mundane solutions which offer nothing more than a common roof.
Data communications equipment in particular offers a challenging number and variety of interconnections to organize and manage from the mechanical standpoint. Complex junction boxes called wiring closets with racks of connectors handle the tangle of interconnections between related circuitry. Iterative interface circuitry may exist for the purpose of routing or multiplexing or may serve solely to convert or adapt signals on one multi-cable system to another format compatible with a different multi-cable system. An example of the latter adapter system is a wiring closet interfacing a set of coaxial cables with a set of unshielded twisted pair cables. Interconnecting these dissimilar types of cables without affecting data throughput requires careful impedance matching typically carried out by dedicated circuitry mounted on a printed circuit board with cable connectors. The numbers of cables involved in a given wiring closet depend, for example, on the size and type of local area network. The overall architecture of the wiring closet should be mechanically sound and easy to install, but should not lose sight of the need for versatility to accommodate networks of various sizes and to allow for easy expansion and change within a given network. Facilitating installation, serviceability and expandability with simple procedures and low cost materials, while maintaining a reasonably high density circuit board enclosure, should be major objectives of the mechanial design.